This study has important strengths that include: 1) providing evidence demonstrating that the miR-26a levels (measured in clinical specimens) are susceptible to modulation by trastuzumab, 2) presenting initial results of the miR-26a analysis, and comparing it with the follow-up findings, in patients with HER-2+ BC and HER-2− BC. This evidence concerns the gene ERBB2 and breast cancer.